A continuously variable transmission (CVT) can be used in a powered vehicle, such as a passenger automobile, for coupling engine power to the driving wheels. Unlike typical transmissions which utilize a number of discrete "gear ratios", CVT's utilize a mechanism whereby the effective gear ratio of the transmission is continuously variable within a predetermined range. The effective gear ratio of a CVT in use at any given time is a function of many variables such as engine load and power output.
A control system is used in conjunction with a CVT to monitor input variables and provide signals to control system parameters such as effective gear ratio and clutch engagement. Such a control system must be economical and efficient, and, especially in a passenger vehicle application, it must cause the CVT to operate smoothly, with little or no hesitation, jerking freewheeling or other performance aberrations that would be unsettling to a driver or passenger.
It is therefore an object of the present invention to provide a control system for continuously variable transmissions that generally overcome the shortcomings and deficiencies of the prior art.
It is a further object of the present invention to provide such a control system that results in good drivability.
It is also an object of the present invention to provide such a control system that enables ample vehicle performance and fuel economy.